This character is really popular in the anime community.
Tips
culture
From Japanese 二次元 (nijigen). Covers anime, manga, light novels, and games (collectively called ACG). Bilibili is China's main 二次元 platform. '三次元' (sāncìyuán) means the real world.
usage
Can be used as an adjective: '很二次元' means something looks or feels anime-like. '二次元少女' = a girl who looks like she stepped out of an anime.